Paper/patches/server/0729-Do-not-run-raytrace-logic-for-AIR.patch
Spottedleaf 01a13871de
Rewrite chunk system (#8177)
Patch documentation to come

Issues with the old system that are fixed now:
- World generation does not scale with cpu cores effectively.
- Relies on the main thread for scheduling and maintaining chunk state, dropping chunk load/generate rates at lower tps.
- Unreliable prioritisation of chunk gen/load calls that block the main thread.
- Shutdown logic is utterly unreliable, as it has to wait for all chunks to unload - is it guaranteed that the chunk system is in a state on shutdown that it can reliably do this? Watchdog shutdown also typically failed due to thread checks, which is now resolved.
- Saving of data is not unified (i.e can save chunk data without saving entity data, poses problems for desync if shutdown is really abnormal.
- Entities are not loaded with chunks. This caused quite a bit of headache for Chunk#getEntities API, but now the new chunk system loads entities with chunks so that they are ready whenever the chunk loads in. Effectively brings the behavior back to 1.16 era, but still storing entities in their own separate regionfiles.

The above list is not complete. The patch documentation will complete it.

New chunk system hard relies on starlight and dataconverter, and most importantly the new concurrent utilities in ConcurrentUtil.

Some of the old async chunk i/o interface (i.e the old file io thread reroutes _some_ calls to the new file io thread) is kept for plugin compat reasons. It will be removed in the next major version of minecraft.

The old legacy chunk system patches have been moved to the removed folder in case we need them again.
2022-09-26 01:02:51 -07:00

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sun, 7 Mar 2021 13:15:04 -0800
Subject: [PATCH] Do not run raytrace logic for AIR
Saves approx. 5% for the raytrace call, as most (expensive)
raytracing tends to go through air and returning early is an
easy win. The remaining problems with this function
are mostly with the block getting itself.
diff --git a/src/main/java/net/minecraft/world/level/BlockGetter.java b/src/main/java/net/minecraft/world/level/BlockGetter.java
index 9cf2f046d50a8a0e08189c9b4b5d2f323d1f790d..d1eefa6ef3e9abfe7af4d8310aa64465fa2d5463 100644
--- a/src/main/java/net/minecraft/world/level/BlockGetter.java
+++ b/src/main/java/net/minecraft/world/level/BlockGetter.java
@@ -84,6 +84,7 @@ public interface BlockGetter extends LevelHeightAccessor {
return BlockHitResult.miss(raytrace1.getTo(), Direction.getNearest(vec3d.x, vec3d.y, vec3d.z), new BlockPos(raytrace1.getTo()));
}
// Paper end
+ if (iblockdata.isAir()) return null; // Paper - optimise air cases
FluidState fluid = iblockdata.getFluidState(); // Paper - don't need to go to world state again
Vec3 vec3d = raytrace1.getFrom();
Vec3 vec3d1 = raytrace1.getTo();